GAP FOSS Column Metadata
This dataset includes zero-filled (presence and absence) observations and catch-per-unit-effort (CPUE) estimates for all identified species at for index stations by the Resource Assessment and Conservation Engineering Division (RACE) Groundfish Assessment Program (GAP) of the Alaska Fisheries Science Center (AFSC). There are no legal restrictions on access to the data. The data from this dataset are shared on the Fisheries One Stop Stop (FOSS) platform (https://www.fisheries.noaa.gov/foss/). The GitHub repository for the scripts that created this code can be found at https://github.com/afsc-gap-products/gap_public_data. For more information about codes used in the tables, please refer to the survey code books (https://www.fisheries.noaa.gov/resource/document/groundfish-survey-species-code-manual-and-data-codes-manual). These data were last updated June 01, 2023.
The Resource Assessment and Conservation Engineering Division (RACE) Groundfish Assessment Program (GAP) of the Alaska Fisheries Science Center (AFSC) conducts fisheries-independent bottom trawl surveys to monitor the condition of the demersal fish and crab stocks of Alaska. These data are developed to describe the temporal distribution and abundance of commercially and ecologically important groundfish species, examine the changes in the species composition of the fauna over time and space, and describe the physical environment of the groundfish habitat.
There are no legal restrictions on access to the data. They reside in the public domain and can be freely distributed. Users must read and fully comprehend the metadata prior to use. Data should not be used beyond the limits of the source scale. Acknowledgement of NOAA, as the source from which these data were obtained, in any publications and/or other representations of these data, is suggested. These data are compiled and approved annually after each summer survey season. The data from previous years are unlikely to change substantially once published.
These data are zero-filled (presence and absence) observations from surveys conducted on fishing vessels. These surveys monitor trends in distribution and abundance of groundfish, crab, and bottom-dwelling species in Alaska’s marine ecosystems. These data include estimates of catch-per-unit-effort (CPUE) for all identified species for index stations. Some survey data are excluded, such as non-standard stations, surveys completed in earlier years using different/non-standard gear, and special tows and non-standard data collections.
Though not included in the public data, these surveys also collect oceanographic and environmental data, and biological data such as length, weight, stomach contents (to learn more about diet), otoliths (fish ear bones to learn about age), and tissue samples for genetic analysis, all of which can be shared upon special request. Also not included in the public data are estimated biomass (average total weight of all fish and crabs sampled) of crabs and groundfish that support the creation of annual stock assessments.
| Column name | Column name (long) | Units | Description |
|---|---|---|---|
| year | Year | year | Year the survey was conducted in. |
| srvy | Survey | text abbreviated | Abbreviated survey names. The column ‘srvy’ is associated with the ‘survey’ and ‘survey_id’ columns. Northern Bering Sea (NBS), Southeastern Bering Sea (EBS), Bering Sea Slope (BSS), Gulf of Alaska (GOA), Aleutian Islands (AI). |
| survey | Survey Name | text | Name and description of survey. The column ‘survey’ is associated with the ‘srvy’ and ‘survey_id’ columns. |
| survey_definition_id | Survey ID | ID code | This number uniquely identifies a survey. Name and description of survey. The column ‘survey_id’ is associated with the ‘srvy’ and ‘survey’ columns. For a complete list of surveys, review the code books. |
| cruise | Cruise ID | ID code | This is a six-digit number identifying the cruise number of the form: YYYY99 (where YYYY = year of the cruise; 99 = 2-digit number and is sequential; 01 denotes the first cruise that vessel made in this year, 02 is the second, etc.). |
| haul | Haul Number | ID code | This number uniquely identifies a sampling event (haul) within a cruise. It is a sequential number, in chronological order of occurrence. |
| hauljoin | Haul ID | ID code | This is a unique numeric identifier assigned to each (vessel, cruise, and haul) combination. |
| stratum | Stratum ID | ID code | RACE database statistical area for analyzing data. Strata were designed using bathymetry and other geographic and habitat-related elements. The strata are unique to each survey series. Stratum of value 0 indicates experimental tows. |
| station | Station ID | ID code | Alpha-numeric designation for the station established in the design of a survey. |
| vessel_name | Vessel Name | text | Name of the vessel used to collect data for that haul. The column ‘vessel_name’ is associated with the ‘vessel_id’ column. Note that it is possible for a vessel to have a new name but the same vessel id number. For a complete list of vessel ID codes, review the code books. |
| vessel_id | Vessel ID | ID code | ID number of the vessel used to collect data for that haul. The column ‘vessel_id’ is associated with the ‘vessel_name’ column. Note that it is possible for a vessel to have a new name but the same vessel id number. For a complete list of vessel ID codes, review the code books. |
| date_time | Date and Time of Haul | MM/DD/YYYY HH::MM | The date (MM/DD/YYYY) and time (HH:MM) of the beginning of the haul. |
| latitude_dd_start | Start Latitude (decimal degrees) | decimal degrees | Latitude (one hundred thousandth of a decimal degree) of the start of the haul. |
| longitude_dd_start | Start Longitude (decimal degrees) | decimal degrees | Longitude (one hundred thousandth of a decimal degree) of the start of the haul. |
| latitude_dd_end | End Latitude (decimal degrees) | decimal degrees | Latitude (one hundred thousandth of a decimal degree) of the end of the haul. |
| longitude_dd_end | End Longitude (decimal degrees) | decimal degrees | Longitude (one hundred thousandth of a decimal degree) of the end of the haul. |
| species_code | Taxon Code | ID code | The species code of the organism associated with the ‘common_name’ and ‘scientific_name’ columns. For a complete species list, review the code books. |
| itis | ITIS Taxonomic Serial Number | ID code | Species code as identified in the Integrated Taxonomic Information System (https://itis.gov/). |
| worms | World Register of Marine Species Taxonomic Serial Number | ID code | Species code as identified in the World Register of Marine Species (WoRMS) (https://www.marinespecies.org/). |
| common_name | Taxon Common Name | text | The common name of the marine organism associated with the ‘scientific_name’ and ‘species_code’ columns. For a complete species list, review the code books. |
| scientific_name | Taxon Scientific Name | text | The scientific name of the organism associated with the ‘common_name’ and ‘species_code’ columns. For a complete taxon list, review the code books. |
| taxon_confidence | Taxon Confidence Rating | category | Confidence in the ability of the survey team to correctly identify the taxon to the specified level, based solely on identification skill (e.g., not likelihood of a taxon being caught at that station on a location-by-location basis). Quality codes follow: ‘High’: High confidence and consistency. Taxonomy is stable and reliable at this level, and field identification characteristics are well known and reliable. ‘Moderate’: Moderate confidence. Taxonomy may be questionable at this level, or field identification characteristics may be variable and difficult to assess consistently. ‘Low’: Low confidence. Taxonomy is incompletely known, or reliable field identification characteristics are unknown. Documentation: Species identification confidence in the eastern Bering Sea shelf survey (1982-2008), Species identification confidence in the eastern Bering Sea slope survey (1976-2010), and Species identification confidence in the Gulf of Alaska and Aleutian Islands surveys (1980-2011). |
| cpue_kgkm2 | Weight CPUE (kg/km2) | kilograms per kilometers squared | Catch weight (kilograms) divided by area (squared kilometers) swept by the net. |
| cpue_nokm2 | Number CPUE (no/km2) | count per kilometers squared | Catch number (in number of organisms) per area (squared kilometers) swept by the net. |
| weight_kg | Taxon Weight (kg) | kilograms | Weight (thousandths of a kilogram) of individuals in a haul by taxon. |
| count | Taxon Count | count, whole number resolution | Total number of individuals caught in haul by taxon, represented in whole numbers. |
| bottom_temperature_c | Bottom Temperature (Degrees Celsius) | degrees Celsius | Bottom temperature (tenths of a degree Celsius); NA indicates removed or missing values. |
| surface_temperature_c | Surface Temperature (Degrees Celsius) | degrees Celsius | Surface temperature (tenths of a degree Celsius); NA indicates removed or missing values. |
| depth_m | Depth (m) | degrees Celsius | Bottom depth (tenths of a meter). |
| distance_fished_km | Distance Fished (km) | degrees Celsius | Distance the net fished (thousandths of kilometers). |
| net_width_m | Net Width (m) | meters | Measured or estimated distance (meters) between wingtips of the trawl. |
| net_height_m | Net Height (m) | meters | Measured or estimated distance (meters) between footrope and headrope of the trawl. |
| area_swept_km2 | Area Swept (km) | kilometers | The area the net covered while the net was fishing (kilometers squared), defined as the distance fished times the net width. |
| duration_hr | Tow Duration (decimal hr) | hours, tenths resolution | This is the elapsed time between start and end of a haul (decimal hours). |
| performance | Haul Performance Code | category | This denotes what, if any, issues arose during the haul. For more information, review the code books. |
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